Cell Biology Quiz: Cell Theory and Types

Prokaryotic Cells
- Lack a nucleus and membrane-bound organelles.
- Smaller and simpler (e.g., bacteria).
- DNA is circular and located in the nucleoid region.
Eukaryotic Cells
- Contain a nucleus and membrane-bound organelles.
- Larger and more complex (e.g., plant and animal cells).
- DNA is linear and associated with histones.

Nucleus:
- Contains cell's genetic material (DNA).
- Site of transcription.
Mitochondria:
- Powerhouse of the cell; produces ATP through cellular respiration.
- Contains its own DNA.
Ribosomes:
- Sites of protein synthesis.
- Can be free-floating or attached to the endoplasmic reticulum.
Endoplasmic Reticulum (ER):
- Rough ER: Studded with ribosomes; synthesizes proteins.
- Smooth ER: Lacks ribosomes; synthesizes lipids.
Golgi Apparatus:
- Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
Lysosomes:
- Contain digestive enzymes to break down waste materials and cellular debris.
Chloroplasts (in plant cells):
- Site of photosynthesis; convert light energy into chemical energy.
- Contains chlorophyll and its own DNA.
Cell Membrane:
- Semi-permeable barrier that controls the movement of substances in and out of the cell.
- Comprised of a phospholipid bilayer with embedded proteins.

Mitosis:
- Process of cell division resulting in two identical daughter cells.
- Stages: Prophase, Metaphase, Anaphase, Telophase.
Meiosis:
- Process of cell division that produces gametes (sperm and egg).
- Involves two rounds of division: Meiosis I and Meiosis II.

Cells communicate through signaling molecules (e.g., hormones, neurotransmitters).
Receptors on cell membranes receive signals and initiate responses.
Types of signaling:
- Autocrine: Signals affecting the same cell.
- Paracrine: Signals affecting nearby cells.
- Endocrine: Signals affecting distant cells (via the bloodstream).

Catabolism: Breakdown of molecules to obtain energy.
Anabolism: Synthesis of complex molecules from simpler ones, requiring energy.

Passive Transport: Movement of substances across the membrane without energy (e.g., diffusion, osmosis).
Active Transport: Movement of substances against their concentration gradient, requiring energy (e.g., sodium-potassium pump).

Cells can adapt to changes in their environment (e.g., increased surface area for absorption, changes in enzyme production based on substrate availability).

Undifferentiated cells with the potential to develop into various cell types.
Types:
- Embryonic stem cells: Pluripotent; can develop into any cell type.
- Adult stem cells: Multipotent; limited to certain cell types.

All living organisms are made of cells, making them the fundamental unit of life.
Cells arise from pre-existing cells, supporting the continuity of life.

Prokaryotic Cells
- Lack a nucleus and membrane-bound organelles; generally smaller and simpler, found in bacteria.
- DNA is circular and located in the nucleoid region of the cell.
Eukaryotic Cells
- Contain a nucleus and organelles; larger and more complex, found in plants and animals.
- DNA is linear and associated with histones, which help package DNA.

Nucleus
- Houses the cell's genetic material (DNA) and is the site for transcription where mRNA is synthesized.
Mitochondria
- Known as the powerhouse of the cell, responsible for ATP production through cellular respiration.
- Contains its own mitochondrial DNA.
Ribosomes
- Protein synthesis occurs here; may be free-floating in the cytoplasm or attached to the endoplasmic reticulum.
Endoplasmic Reticulum (ER)
- Rough ER: Studded with ribosomes; primarily synthesizes proteins.
- Smooth ER: Lacks ribosomes; primarily synthesizes lipids.
Golgi Apparatus
- Modifies, sorts, and packages proteins and lipids for secretion or further delivery within the cell.
Lysosomes
- Contains digestive enzymes; breaks down waste materials and cellular debris.
Chloroplasts (present in plant cells)
- Site of photosynthesis, converting light energy into chemical energy through chlorophyll; also contains its own DNA.
Cell Membrane
- Forms a semi-permeable barrier regulating the movement of substances in and out of the cell, structured as a phospholipid bilayer with embedded proteins.

Mitosis
- Cellular division resulting in two genetically identical daughter cells, comprising stages: Prophase, Metaphase, Anaphase, and Telophase.
Meiosis
- Specialized cellular division that produces gametes (sperm and egg) involving two rounds of division: Meiosis I and II, leading to genetic variation.

Cells utilize signaling molecules, such as hormones and neurotransmitters, to communicate.
Receptors on cell membranes detect signals to initiate cellular responses.
Types of signaling include:
- Autocrine: Affects the same cell emitting the signal.
- Paracrine: Affects nearby cells.
- Endocrine: Affects distant cells through the bloodstream.

Catabolism: Breakdown of molecules to release energy for cellular processes.
Anabolism: Constructing complex molecules from simpler ones, consuming energy.

Passive Transport: Movement across the membrane that does not require energy, including diffusion and osmosis.
Active Transport: Requires energy to move substances against their concentration gradient, exemplified by the sodium-potassium pump.

Cells adapt to environmental changes, enhancing functions (like increased surface area for absorption) or modifying enzyme production based on the presence of substrates.

Undifferentiated cells with the potential to transform into various types of cells.
Embryonic Stem Cells: Pluripotent, can differentiate into any cell type.
Adult Stem Cells: Multipotent, capable of forming a limited range of cell types, typically related to specific tissues.